Surgical torque wrench

Abstract

A surgical torque wrench having jaws for application to a rotating part and a handle removably secured to the jaws. The jaws and handle are secured together about a pivot that is parallel to the axis of rotation of the rotating part. A securing device is fitted between the jaws and the handle which secures them relative to each other in a given angular position and is releasable when a given torque is reached. A removable handle member is provided to fix the jaws to the handle to allow for application of torque.

What is claimed is: 
     
       1. A surgical torque wrench, comprising: (a) a jaw part adapted for application to an element to be turned;   (b) a handle part adjoining said jaw part for turning said jaw part; wherein: said jaw part is joined to said handle part, and is pivotable with respect to said handle part about a pivot axis from an operative position to an overload position when a torque exceeding a predetermined torque is exerted on said handle part; and   said pivot axis extends parallel to an axis of rotation of the element to be turned;     (c) a spring;   (d) a holding device provided between the jaw part and the handle part; wherein: said holding device is biased by said spring for fixing said jaw part in said operative position at a first angular position relative to said handle part when a torque less than the predetermined torque is exerted on said handle part;   said holding device is releasable to allow said jaw part to pivot from said operative position into said overload position at a second angular position relative to said handle part when a torque exceeding the predetermined torque is exerted on said handle part; and   once said jaw part has entered said overload position, said spring biases said holding device to bias said jaw part back into said operative position; and     (e) a locking element movable with respect to said handle part between first and second positions; wherein: in said first position, said locking element embraces a portion of said jaw part to prevent removal of said jaw part from said handle part; and   in said second position, said locking element releases said portion of said jaw part to allow said jaw part to pivot from said operational position in a direction away from said overload position to facilitate removal of said jaw part from said handle part.     
     
     
       2. The surgical torque wrench of claim 1, wherein: said locking element comprises a handle sleeve surrounding said handle part, at least in part, and adapted to be secured thereto at said first and second positions along a longitudinal axis of said handle part.   
     
     
       3. The surgical torque wrench of claim 2, wherein: in said first position, handle sleeve enables pivoting of said jaw part relative to said handle part in one direction only.   
     
     
       4. The surgical torque wrench of claim 2, wherein: said handle part comprises a cylindrical guide sleeve having a piston-shaped guide body mounted for longitudinal displacement therein and receiving said spring; and   said handle sleeve is pushable over said guide sleeve and is releasably connectable to said guide sleeve.   
     
     
       5. The surgical torque wrench of claim 4, wherein: said handle sleeve is adapted to threadedly engage said guide sleeve in said first and second positions.   
     
     
       6. The surgical torque wrench of claim 4, wherein: said handle sleeve covers said guide sleeve and a closure plug inserted therein.   
     
     
       7. The surgical torque wrench of claim 4, wherein: in said first position, said handle sleeve is completely pushed onto said guide sleeve, and forms a stop for said jaw part which enables pivoting of said jaw part relative to said handle part in one direction only from said operative position.   
     
     
       8. The surgical torque wrench of claim 2, wherein: said second position is rearward of said first position on said handle part.   
     
     
       9. The surgical torque wrench of claim 1, wherein: said pivot axis is arranged between a jaw of said jaw part and a rear end of said jaw part; and   said holding device engages said rear end of said jaw part.   
     
     
       10. The surgical torque wrench of claim 9, wherein: said pivot axis is spaced at a considerably smaller distance from said jaw than from said rear end.   
     
     
       11. The surgical torque wrench of claim 1, wherein: said handle part comprises two parallel arms, between which said jaw part is received; and   said pivot axis of said jaw part is arranged at a front end of said parallel arms.   
     
     
       12. The surgical torque wrench of claim 11, further comprising: a web joining said two arms; wherein: said web forms a stop that limits a pivot angle of said jaw part relative to said handle part when said holding device is released.     
     
     
       13. The surgical torque wrench of claim 1, wherein: said holding device is a form-locking device with a fixed release force.   
     
     
       14. The surgical torque wrench of claim 13, wherein: said holding device comprises a spring-loaded detent member which is displaceable in a direction towards said pivot axis, and which engages a recess on said jaw part and is lifted out of said recess against a bias of said spring when a torque exceeding said predetermined torque is applied to said handle part.   
     
     
       15. The surgical torque wrench of claim 14, wherein: said recess on said jaw part is an arcuate recess in a rear end edge of said jaw part.   
     
     
       16. The surgical torque wrench of claim 15, wherein: said rear end edge is inclined slightly in relation to a tangent to a circle drawn about said pivot axis of said jaw part.   
     
     
       17. The surgical torque wrench of claim 14, wherein: said detent member comprises a roller which is rotatable parallel to said pivot axis of said jaw part.   
     
     
       18. The surgical torque wrench of claim 17, wherein: said roller comprises a ball bearing.   
     
     
       19. The surgical torque wrench of claim 17, wherein: said roller comprises a packed ball bearing which is filled with a sterilizable grease.   
     
     
       20. The surgical torque wrench of claim 14, wherein: the spring loading of said detent member is adjustable.   
     
     
       21. The surgical torque wrench of claim 20, further comprising: an adjustable support for said spring for providing adjustment of said spring loading.   
     
     
       22. The surgical torque wrench of claim 14, wherein: said detent member is mounted for longitudinal displacement in said handle part.   
     
     
       23. The surgical torque wrench of claim 22, further comprising: a guide body which is longitudinally displaceable in said handle part; wherein: said detent member is mounted in said guide body; and   said spring is supported on said handle part and engages said guide body.     
     
     
       24. The surgical torque wrench of claim 23, wherein: said handle part comprises a cylindrical guide sleeve having a piston-shaped guide body mounted for longitudinal displacement therein and receiving said spring.   
     
     
       25. The surgical torque wrench of claim 24, wherein: said guide body and said guide sleeve form a lubricant-free plastic-metal pairing.   
     
     
       26. The surgical torque wrench of claim 25, wherein: said guide body comprises polyetherketone and said guide sleeve comprises stainless steel.   
     
     
       27. The surgical torque wrench of claim 24, wherein: said guide body is secured in said guide sleeve against rotation about a longitudinal axis of said guide sleeve.   
     
     
       28. The surgical torque wrench of claim 24, wherein: said guide sleeve has side openings to facilitate sterilization of an interior of said guide sleeve.   
     
     
       29. The surgical torque wrench of claim 24, wherein: said guide sleeve has a closure plug on which there is arranged an adjustable spacer for a pressure spring support.   
     
     
       30. The surgical torque wrench of claim 29, wherein: said adjustable spacer comprises an adjusting screw which rests against a pressure plate which is longitudinally displaceable in said guide sleeve.   
     
     
       31. The surgical torque wrench of claim 30, wherein: said adjusting screw is countersunk in a threaded bore of said closure plug; and   said threaded bore is closed by a plug inserted therein.   
     
     
       32. The surgical torque wrench of claim 31, wherein: said plug inserted in said threaded bore is a threaded plug.   
     
     
       33. The surgical torque wrench of claim 1, wherein: a pivot bearing of said jaw part is releasable on said handle part.   
     
     
       34. The surgical torque wrench of claim 33, further comprising: a bearing shaft that is axially displaceably arranged on said handle part between a bearing position in which it extends through a bearing opening of said jaw part, and a release position, in which it is pulled out of said bearing opening.   
     
     
       35. The surgical torque wrench of claim 34, wherein: said bearing shaft is undetachably held on said handle part.   
     
     
       36. The surgical torque wrench of claim 35, wherein: a projection is arranged on said handle part; and   said projection engages in a longitudinal groove of said bearing shaft.   
     
     
       37. The surgical torque wrench of claim 36, wherein: said longitudinal groove of said bearing shaft has an end region bending around in a circumferential direction and extending at an incline to the longitudinal axis of said bearing shaft; and   a turning grip is arranged on said bearing shaft.   
     
     
       38. The surgical torque wrench of claim 37, wherein: a recess is arranged in said longitudinal groove at an end of said inclined end region of said longitudinal groove;   said recess extends in the longitudinal direction of said bearing shaft and receives said projection on said handle part in said bearing position of said bearing shaft; and   in said bearing position, said bearing shaft is resiliently pressed against said projection on said handle part.   
     
     
       39. The surgical torque wrench of claim 38, further comprising: a pressure member mounted in said bearing shaft that protrudes from an end face of said bearing shaft and is resiliently pressable into said bearing shaft.   
     
     
       40. The surgical torque wrench of claim 39, wherein: said pressure member is a ball.   
     
     
       41. The surgical torque wrench of claim 39, wherein: said pressure member projects into an insertion space of said jaw part in the release position of said bearing shaft.